Production of hybrid seed for commercial sale is a large industry. Hybrid plants grown from hybrid seed benefit from the heterotic effects of crossing two genetically distinct breeding lines with the result that the agronomic performance of the offspring is superior to both parents, typically in vigour, yield, and uniformity. The better performance of hybrid seed varieties compared to open-pollinated varieties makes the hybrid seed more attractive for farmers to plant and thereby commands a premium price in the market place.
Genic male sterility has been utilized in hybrid seed production. Various methods of genic male sterility production and hybrid seed production using male sterile plants are described by the present inventors in published Australian Patent Application Serial No. 611258 and in published PCT Application No. PCT/CA90/00037 by Paladin Hybrids.
Other male sterility systems are disclosed for example in PCT Application No. PCT/WO89/10396 by Plant Genetic Systems.